The present invention relates to a device for the perception of gas flow. The device is installed in a gas supply line between the point of origin of the gas supply and a gas utilizing tool. The inside of an air-tight chamber is sectioned off into an upper chamber and a lower chamber by a diaphragm. The inlet and outlet for the supply of gas are introduced into the lower chamber. The inlet and outlet each have an airpipe leading to and being in communication with the upper chamber. A valve for opening and shutting of the gas outlet is positioned on the outlet side of the device, in the lower chamber.